Polar modulation is a technique in which a signal, or carrier, having a constant radian frequency ω, is time-varied in both magnitude and phase. Typically, polar transmitters receive baseband signals represented in Cartesian form as in-phase (I) and quadrature (Q) component signals, which are naturally symmetric. The I and Q baseband component signals are then converted into a polar form that is represented in terms of corresponding R and θ component signals. This conversion may be performed by a coordinate rotation digital computer (CORDIC) algorithm.
The R and θ signals are processed in separate amplitude and phase paths and may be recombined at the output of the power amplifier. Timing misalignments between the amplitude and phase signals may occur. Such timing misalignments are detrimental to signal quality. For instance, timing misalignments may impair the downstream reconstruction of the corresponding I and Q component signals.
The delays associated with R and θ paths are not necessarily static. For instance, such delays may vary with transmit power level. Therefore, dynamic alignment of R and θ paths during operation may be desirable.